Wigan will be without Amos Roberts for eight weeks after a scan revealed the 29-year-old utility back has ruptured his posterior cruciate knee ligament.

The incident happened during Monday's 54-14 win over Wakefield when Roberts collided with a post. The Wigan coach, Michael Maguire, initially feared that Roberts had broken his leg, but the player will now undergo further tests to determine the best course of treatment.

"Amos has been enjoying his football and has been doing a great job for us, but we've got some good people who can come into the team," said Maguire. "I know Amos will work extra hard to get back to full fitness as soon as possible."

Roberts has played a key role in guiding Wigan to nine wins from their 10 games so far this season, scoring 12 tries.

Maguire is also waiting for news on the fitness of the hooker Thomas Leuluai ahead of this weekend's game with Salford, with the New Zealand international suffering a bruised foot against Wakefield. The hooker Mark Riddell and forwards Andy Coley and Harrison Hansen are already ruled out.

George Carmont and Cameron Phelps, though, could return from leg injuries.